WO2000046335A1

WO2000046335A1 - Liquid dishwashing detergent compositions containing amylase enzymes

Info

Publication number: WO2000046335A1
Application number: PCT/US2000/003229
Authority: WO
Inventors: Peter Robert Foley
Original assignee: The Procter & Gamble Company
Priority date: 1999-02-08
Filing date: 2000-02-08
Publication date: 2000-08-10
Also published as: AU2874600A; KR20010089638A; JP2002536499A; BR0008066A; EP1151073A1; JP2002536498A; TR200102231T2; EP1151070A1; AR017744A1; CA2360654A1; EP1151074A1; AU2874400A; JP4107633B2; JP2002536497A; WO2000046334A1; EP1151075A1; JP2002536500A; WO2000046331A1; AU2874300A; AU3225400A

Abstract

Liquid dishwashing detergent composition containing one or more amylase enzymes which exhibits excellent starch-based soil removal performance and is devoid of certain amylase enzyme-destabilizing components such as hydrogen peroxide and chelants having a Log K of greater than about 1.5.

Description

LIQUID DISHWASHING DETERGENT COMPOSITIONS CONTAINING AMYLASE ENZYMES

TECHNICAL FIELD

The present invention relates to liquid dishwashing detergent compositions containing amylase enzymes and which exhibit excellent greasy soil removal performance. These compositions are free of certain amylase enzyme-destabilizing components. BACKGROUND OF THE INVENTION

Light-duty liquid (LDL) or gel detergent compositions useful for manual dishwashing are well known in the art. Such products are generally formulated to provide a number of widely diverse performance and aesthetics properties and characteπstics. First and foremost, liquid or gel dishwashing products must be formulated with types and amounts of surfactants and other cleaning adjuvants that will provide acceptable solubihzation and removal of food soils, especially grease, fat and other hydrophobic soils, from dishware being cleaned with aqueous solutions of these dishwashing products.

Heavily soiled dishware can present special problems during manual dishwashing operations. Kitchen articles such as plates, utensils, pots, pans, crockery and the like may be heavily soiled in the sense that relatively large amounts of food soils and residues, particularly polymeπzed and burnt-on greasy soils, may still be found on the dishware at the time such soiled dishware is to be manually washed. Such soil residues may be tenaciously adhered or stuck to the surfaces of the dishware to be cleaned as the result of the food soils present, the nature of the dishware surfaces involved or even the type of cooking operations to which the soiled dishware had been subjected. Starch-based soils are particularly prone to become tenaciously adhered to the side of kitchenware. Thus, there is a continuing effort by formulators of liquid dishwashing compositions to incorporate additional components into LDL detergents to provide consumers with improved cleaning benefits, particularly on the difficult, baked and burnt-on soils which make cleaning kitchenware laborious. One such component which can improve cleaning performance on tenacious soils is amylase enzymes. As a component of a liquid dishwashing detergent, amylase enzymes can be extremely effective at removing starch-based soils and residues adhered to kitchen articles such as cookware and dishware. But while amylase enzymes provide excellent cleaning benefits, it has been difficult to successfully incorporate amylases into a liquid dishwashing detergent formulation because the enzymes tend to be unstable and rapidly degrade, leaving the formulation's amylase enzyme constant at levels far too low to provide adequate cleaning benefits. Thus upon prolonged storage, the formulation's starch-cleaning performance will gradually deteriorate as the amylase enzymes degrade to levels insufficient to provide starch-cleaning benefits.

Given the foregoing, there is a continuing need to formulate manual dishwashing compositions that have improved amylase enzyme stability. Accordingly, it is a benefit of the present invention to provide liquid dishwashing compositions that have excellent amylase enzyme stability and thus provide excellent cleaning benefits even after prolonged storage.

SUMMARY OF THE INVENTION It has now been determined that amylase enzymes are unstable in the presence of a variety of chemical compounds commonly found in liquid dishwashing detergent compositions, and improved amylase enzyme stability may be achieved by excluding these compounds from the liquid detergent composition or keeping the levels of these compounds in the composition as low as possible. Such amylase enzyme-destabihzmg compounds include: hydrogen peroxide, which is often found as an impurity in amme oxide, and chelants which have a relatively high calcium binding constants relative to the calcium binding constant of amylases. Citric acid and its salts are examples of such chelants. Thus certain enzyme destabilizing ingredients that are particularly destabilizing of amylase enzymes are excluded from the composition. Thus this invention relates to a liquid dishwashing detergent composition compπsing: (a) from about 0.0001% to about 5%, of an amylase enzyme; and (b) at least about 0.5% of a suds booster; wherein the composition has especially desirable greasy soil removal performance when used to clean heavily soiled kitchen articles and is substantially free of an ingredient selected from the group consisting of hydrogen peroxide, and chelants having a Log K of greater than about 3.0.

All parts, percentages and ratios used herein are expressed as percent weight unless otherwise specified. All documents cited are, in relevant part, incorporated herein by reference. Unless otherwise noted all pH values reported for a composition are as measured as 10% aqueous solution.

DETAILED DESCRIPTION OF THE INVENTION Definitions - As used herein the term "light duty liquid detergent composition" (LDL) refers to those compositions which are employed in manual (i.e. hand) dishwashing. By "kitchen articles" it is meant cookware, flatware, dishware, silverware and other articles commonly found in the kitchen and used for the preparation, consumption and serving of food as well as those articles used for cleaning up at the conclusion of a meal or other food preparation. By "calcium binding constant" it is meant the metal complex equilibrium constant for

Ca²⁺ ions These values may be found in many standard reference works and are discussed in greater detail below.

By "Log K" it is meant the value of login of the calcium binding constant. ENZYMES Detergent compositions of the present invention comprise at least one amylase enzyme and (if desirable) other enzymes which provide cleaning performance benefits.

Amylase - Amylases (α and/or β) can be included for removal of carbohydrate-based stains. Suitable amylases are Termamyl® (Novo Nordisk), Fungamyl® and BAN® (Novo

Nordisk). The enzymes may be of any suitable origin, such as vegetable, animal, bacterial, fungal and yeast origin. Amylase enzymes are normally incorporated in the detergent composition at levels from about 0.0001% to about 2%, preferably from about 0.0001% to about 0.5%, more preferably from about 0.0005% to about 0.1%.

In one embodiment of the present invention, amylase enzymes are used at very low levels from about 0.0001% to about 0.05%, preferably from about 0.0002% to about 0.02%. Based on experience with other enzyme species, it would seem that the use of such small amounts of amylase enzymes would not enhance cleaning efficacy; but it has been determined in the present invention that appreciable cleaning benefits are obtained even at these low levels.

When enzymes are used in a liquid dishwashing composition, at very low levels, in order to prevent such small amounts of enzyme from becoming quickly destabilized and destroyed it is preferable that certain enzyme destabilizing ingredients (discussed in greater detail below) are excluded from the liquid dishwashing composition.

Amylase enzymes also include those descπbed in W095/26397 and in co-pending application by Novo Nordisk PCT/DK96/00056 Other specific amylase enzymes for use in the detergent compositions of the present invention therefore include : (a) α-amylases characterised by having a specific activity at least 25% higher than the specific activity of Termamyl® at a temperature range of 25°C to 55°C and at a pH value in the range of 8 to 10, measured by the Phadebas® α-amylase activity assay. Such Phadebas® α-amylase activity assay is described at pages 9-10, W095/26397. (b) α-amylases according (a) comprising the amino sequence shown in the SEQ LD listings m the above cited reference, or an α-amylase being at least 80% homologous with the amino acid sequence shown in the SEQ LD listing

(c) α-amylases according (a) obtained from an alkalophilic Bacillus species, comprising the following ammo sequence in the N-terminal : His-His-Asn-Gly-Thr-Asn-Gly-Thr-Met-Met-Gln-

Tyr-Phe-Glu-Trp-Tyr-Leu-Pro-Asn-Asp.

A polypeptide is considered to be X% homologous to the parent amylase if a comparison of the respective ammo acid sequences, performed via algorithms, such as the one described by Lipman and Pearson in Science 227, 1985, p. 1435, reveals an identity of X% (d) α-amylases according (a-c) wherein the α-amylase is obtainable from an alkalophilic Bacillus species; and in particular, from any of the strains NCLB 12289, NCLB 12512, NCLB 12513 and DSM 935

In the context of the present invention, the term "obtainable from" is intended not only to indicate an amylase produced by a Bacillus strain but also an amylase encoded by a DNA sequence isolated from such a Bacillus strain and produced in an host organism transformed with said DNA sequence.

(e) α-amylase showing positive lmmunological cross-reactivity with antibodies raised against an α-amylase having an ammo acid sequence corresponding respectively to those α-amylases m (a- d). (f) Variants of the following parent α-amylases which (l) have one of the ammo acid sequences shown in corresponding respectively to those α-amylases m (a-e), or (n) displays at least 80% homology with one or more of said ammo acid sequences, and/or displays lmmunological cross- reactivity with an antibody raised against an α-amylase having one of said ammo acid sequences, and/or is encoded by a DNA sequence which hybridizes with the same probe as a DNA sequence encoding an α-amylase having one of said amino acid sequence; in which vanants :

1. at least one ammo acid residue of said parent α-amylase has been deleted; and/or

2. at least one ammo acid residue of said parent α-amylase has been replaced by a different amino acid residue; and/or

3. at least one ammo acid residue has been inserted relative to said parent α-amylase; said variant having an α-amylase activity and exhibiting at least one of the following properties relative to said parent α-amylase : increased thermostabihty, increased stability towards oxidation, reduced Ca ion dependency, increased stability and/or α- amylolytic activity at neutral to relatively high pH values, increased α-amylolytic activity at relatively high temperature and increase or decrease of the lsoelectric point (pi) so as to better match the pi value for α-amylase variant to the pH of the medium. Said variants are described in the patent application PCT/DK96/00056.

Other amylases suitable herein include, for example, α-amylases described in GB 1 ,296,839 to Novo; RAPLDASE®, International Bio-Synthetics, Inc. and TERMAMYL®, Novo. FUNGAMYL® from Novo is especially useful. Engineering of enzymes for improved stability, e.g., oxidative stability, is known. See, for example J. Biological Chem., Vol 260, No. 11, June 1985, pp. 6518-6521. Certain preferred embodiments of the present compositions can make use of amylases having improved stability m detergents such as automatic dishwashing types, especially improved oxidative stability as measured against a reference-point of TERMAMYL® in commercial use in 1993. These preferred amylases herein share the characteristic of being "stability-enhanced" amylases, characterized, at a minimum, by a measurable improvement in one or more of: oxidative stability, e.g., to hydrogen peroxide/tetraacetylethylenediamine m buffered solution at pH 9-10; thermal stability, e.g., at common wash temperatures such as about 60°C; or alkaline stability, e.g., at a pH from about 8 to about 1 1, measured versus the above-identified reference-point amylase. Stability can be measured using any of the art-disclosed technical tests. See, for example, references disclosed in WO 9402597. Stability-enhanced amylases can be obtained from Novo or from Genencor International. One class of highly preferred amylases herein have the commonality of being derived using site -directed mutagenesis from one or more of the Bacillus amylases, especially the Bacillus α-amylases, regardless of whether one, two or multiple amylase strains are the immediate precursors. Oxidative stability-enhanced amylases vs the above-identified reference amylase are preferred for use, especially m bleaching, more preferably oxygen bleaching, as distinct from chlonne bleaching, detergent compositions herein. Such preferred amylases include (a) an amylase according to the hereinbefore incorporated WO 9402597, Novo, Feb. 3, 1994, as further illustrated by a mutant m which substitution is made, using alanme or threonine, preferably threomne, of the methio ne residue located in position 197 of the B. licheniformis alpha-amylase, known as TERMAMYL®, or the homologous position variation of a similar parent amylase, such as B. amylohquefaciens, B. subtihs, or B. stearothermophilus; (b) stability-enhanced amylases as descπbed by Genencor International in a paper entitled "Oxidatively Resistant alpha- Amylases" presented at the 207th American Chemical Society National Meeting, March 13-17 1994, by C. Mitchinson. Therein it was noted that bleaches in automatic dishwashing detergents inactivate alpha-amylases but that improved oxidative stability amylases have been made by Genencor from B. licheniformis NCLB8061. Methionine (Met) was identified as the most likely residue to be modified. Met was substituted, one at a time, in positions 8, 15, 197, 256, 304, 366 and 438 leading to specific mutants, particularly important being M197L and M197T with the M197T variant being the most stable expressed variant. Stability was measured in CASCADE® and SUNLIGHT®, (c) particularly preferred amylases herein include amylase variants having additional modification m the immediate parent as described in WO 9510603 A and are available from the assignee, Novo, as

DURAMYL®. Other particularly preferred oxidative stability enhanced amylase include those described in WO 9418314 to Genencor International and WO 9402597 to Novo. Any other oxidative stability-enhanced amylase can be used, for example as derived by site-directed mutagenesis from known chimeric, hybrid or simple mutant parent forms of available amylases Other preferred enzyme modifications are accessible. See WO 9509909 A to Novo

Other Enzymes - Although amylase enzymes provide excellent cleaning benefits when included m a detergent composition, it is preferred that they be used as one part of a cocktail of conventional applicable enzymes like protease, amylase, hpase, cutinase and/or cellulase. Enzymes when present in the compositions, at from about 0.0001% to about 5% of active enzyme by weight of the detergent composition. Other enzymes suitable for use in the present invention include cellulases, hemicellulases, peroxidases, proteases, hpases, cutinases, pectmases, xylanases, reductases, oxidases, phenoloxidases, hpoxygenases, gnmases, pullulanases, tannases, pentosanases, malanases, β-glucanases, arabinosidases or mixtures thereof. Preferred proteolytic enzymes, then, are selected from the group consisting of Alcalase ® (Novo Industπ A/S), BPN', Protease A and Protease B (Genencor), and mixtures thereof. Protease B is most preferred.

Further non-hmitmg examples of suitable and preferred enzymes are disclosed in U. S. Pat. No. 5,990,065, to Vinson et al., issued Nov. 23, 1999, which is hereby incorporated by reference.

Enzyme Stability and H^O? Impurities - Because even small amounts of hydrogen peroxide can impair enzyme stability in a liquid detergent composition it is important that hydrogen peroxide levels m the liquid detergent be kept as low as possible; thus the present compositions preferably contain less than 0.02% hydrogen peroxide, more preferably less than 0.005% hydrogen peroxide, and most preferably will contain no detectable amounts of hydrogen peroxide. It is preferable to minimize hydrogen peroxide levels in the present compositions by reducing to the maximum extent possible the amount of hydrogen peroxide in the component raw materials. But still another way to minimize hydrogen peroxide levels is to add antioxidants to the compositions; these antioxidants reduce the hydrogen peroxide levels Any conventional antioxidant used in detergent compositions may be used, such as 2,6-dι-tert-butyl-4-methylphenol (BHT), carbamate, ascorbate, thiosulfate, monoethanolamιne(MEA), diethanolamme, tπethanolamine, etc Also suitable are any of the diamine compounds discussed in detail below It is preferred that the antioxidant, when present, be present m the composition from about 0.001% to about 5% by weight.

When antioxidants are to be used to reduce hydrogen peroxide levels it is important that the antioxidants be added before the amylase enzymes are added so that as much hydrogen peroxide as possible will be removed from the composition, thus reducing the amount of amylase enzymes destroyed by interaction with the hydrogen peroxide

One raw material component in which hydrogen peroxide is often found as an impurity is amine oxide and amine oxide surfactant pastes, which is often added to LDL detergents to function as both a surfactant and a suds booster As discussed above, it is desirable that hydrogen peroxide impurities be removed from the amme oxide or amine oxide surfactant paste so that they contain as little hydrogen peroxide as possible When it is not possible or desirable to remove hydrogen peroxide from the amine oxide, antioxidants may be added directly to the amme oxide to remove the hydrogen peroxide before the amine oxide is added to the liquid detergent composition during manufacture; in this situation the amme oxides will preferably contain from about 0.01% to about 0.7%, preferably from about 0 05% to about 0.2% of antioxidants. But the method or type of process for removing hydrogen peroxide is not as important as that fact that m one embodiment of the present invention amme oxide is produced which contains hydrogen peroxide and that hydrogen peroxide is subsequently removed from the amine oxide that is important.

It has been determined in the present invention that amylase enzymes are even less stable than other types of enzymes m the presence of hydrogen peroxide. (One particular amylase enzyme type that is less stable than even other types of amylase enzymes in the presence of hydrogen peroxide, is an α-amylase enzyme having a specific activity at least 25% higher than the specific activity of Termamyla at a temperature range of 25°C to 55°C and at a pH value in the range of 8 to 10, measured by the Phadebasa a-amylase activity assay.) The addition of diols can also improve the enzymatic stability of a liquid dishwashing composition. Diols suitable for use m the present invention have the following formula:

wherein n = 0- 3, R₇ = H, methyl or ethyl; and R₈ = H, methyl, ethyl, propyl, isopropyl, butyl and isobutyl. Preferred diols include propylene glycol, 1,2 hexanediol, 2-ethyl-l,3-hexanedιol and 2,2,4-trιmethyl-l,3-pentanedιol. When diols are present While the deleterious effects are not as severe enzyme stability may also be adversely affected by certain citric acid and salts thereof (citrates), as is discussed below in the section on builder materials.

SURFACTANTS The compositions of this invention comprise from about 5 % to about 90 %, more preferably from about 25 % to about 70 % by weight surfactant.

Anionic Surfactants - The anionic surfactants useful in the present invention are preferably selected from the group consisting of linear alkylbenzene sulfonate, alpha olefin sulfonate, paraffin sulfonates, alkyl ester sulfonates, alkyl sulfates, alkyl alkoxy sulfate, alkyl sulfonates, alkyl alkoxy carboxylate, alkyl alkoxylated sulfates, sarcosmates, tauπnates, and mixtures thereof. An effective amount, typically from about 0.5% to about 90%, preferably about 5% to about 50%, more preferably from about 10 to about 30%, by weight of anionic detersive surfactant can be used m the present invention.

Suitable examples of anionic surfactants may be found in copending provisional patent application of Chandπka Kastuπ et al., entitled "Liquid Detergent Compositions Comprising Polymeπc Suds Enhancers", having P & G Case No. 6938P, seπal no. 60/066,344 and filed on November 21, 1997, which is hereby incorporated by reference. Further examples of suitable anionic surfactants are given m "Surface Active Agents and Detergents" (Vol. I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Patent 3,929,678, issued December 30, 1975 to Laughlin, et al. at Column 23, line 58 through

Column 29, line 23. Suitable anionic surfactants may further be found m U.S. Pat. No. 5,415,814 issued 16 May 1995, to Ofosu-Asante et al., all of which are hereby incorporated by reference

Amphoteπc surfactants - The amphoteπc surfactants useful m the present invention are preferably selected from amme oxide surfactants. Amme oxides are semi-polar nomonic surfactants and include water-soluble amine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms.

Semi-polar amphoteπc detergent surfactants including amine oxide surfactants are discussed in greater detail in U.S. Pat. No. 5,167,872, issued December 1, 1992, to Pancheπ et al. These amine oxide surfactants in particular include C \ Q-C i g alkyl dimethyl amine oxides and Cg-Ci2 alkoxy ethyl dihydroxy ethyl amine oxides

Also suitable are amine oxides such as propyl amine oxides, represented by the formula:

wherein R_{ is an alkyl, 2-hydroxyalkyl, 3 -hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from about 8 to about 18 carbon atoms, R₂ and

R₃ are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3- hydroxypropyl and n is from 0 to about 10.

Other suitable, non-hmitmg examples of amphoteπc detergent surfactants that are useful in the present invention include amido propyl betaines and derivatives of aliphatic or heterocychc secondary and ternary amines in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 24 carbon atoms and at least one aliphatic substituent contains an anionic water-solubihzing group.

Further examples of suitable amphoteπc surfactants are given in "Surface Active Agents and Detergents" (Vol. I and LI by Schwartz, Perry and Berch), hereby incorporated by reference. Preferably the amphoteπc surfactant is present in the composition in an effective amount, more preferably from about 0.1% to about 20%, even more preferably about 0.1% to about 15%, even more preferably still from about 0.5% to about 10%,by weight.

Nomonic Surfactants - Examples of noniomc detergent surfactants that are useful in the present invention are generally disclosed in U.S. Pat. No. 3,929,678, Laughlin et al., issued Dec. 30, 1975, at column 13, line 14 through column 16, line 6, incorporated herein by reference. These include:

(i) the polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols.; (π) alcohol ethoxylates which are the condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide. They are represented by the general formula:

R(OCH₂CH₂)_nOH

(in) another type of noniomc co-surfactant suitable for use in combination with the polyhydroxy fatty acid amides in the noniomc surfactant component herein comprises the ethylene oxide-propylene oxide block co-polymers that function as polymeric surfactants (these are also discussed separately under the solvents heading);

(IV) the condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol; and (v) alkylpolysacchaπdes disclosed in U.S. Pat. No. 4,565,647, Llenado, issued Jan

21, 1986, having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably from about 10 to about 16 carbon atoms and a polysaccharide.

Secondary Surfactants - Secondary detersive surfactant can be selected from the group consisting of catiomcs, ampholytics, zwitteπonics, and mixtures thereof. By selecting the type and amount of detersive surfactant, along with other adjunct ingredients disclosed herein, the present detergent compositions can be formulated to be used m the context of laundry cleaning or in other different cleaning applications, particularly including dishwashing. The particular surfactants used can therefore vary widely depending upon the particular end-use envisioned.

Suitable secondary surfactants are described in detail in the copendmg provisional patent application of Chandrika Kastuπ et al., entitled "Liquid Detergent Compositions Comprising

Polymeπc Suds Enhancers", having P & G Case No. 6938P, application seπal no. 60/066,344, incorporated above.

Diamines - Diammes used herein in detergent compositions in combination with detersive surfactants at levels and ratios (discussed in further detail below) which are effective for achieving at least a directional improvement in cleaning performance. In the context of a hand dishwashing composition, such "usage levels" can vary depending not only on the type and seventy of the soils and stains, but also on the wash water temperature, the volume of wash water and the length of time the dishware is contacted with the wash water. Since the habits and practices of the users of detergent compositions show considerable variation, the composition will preferably contain at least about 0.1%, more preferably at least about 0.2%, even more preferably, at least about 0.25%, even more preferably still, at least about 0.5% by weight of said composition of diamine. The composition will also preferably contain no more than about 15%, more preferably no more than about 10%, even more preferably, no more than about 6%, even more preferably, no more than about 5%, even more preferably still, no more than about 1 5% by weight of said composition of diamine.

In one of its several aspects, this invention provides a means for enhancing the removal of greasy/oily soils by combining the specific diamines of this invention with surfactants. Greasy/oily "everyday" soils are a mixture of triglycendes, lipids, complex polysaccharides, fatty acids, inorganic salts and protemaceous matter.

Thus diamines, in combination with amphoteπc and anionic surfactants in the specific ratios discussed below, offer the benefit of improved grease and tough food cleaning which allows the elimination or reduction in the amount of divalent ions in the preferred embodiments of the present formula. This improved cleaning is a result of diammes' proclivity as a buffering agent to increase the alkalinity of the dishwashing composition.

It is preferred that the diammes used in the present invention are substantially free from impunties. That is, by "substantially free" it is meant that the diammes are over 95% pure, i.e., preferably 97%, more preferably 99%, still more preferably 99.5%, free of impurities. Examples of impurities which may be present in commercially supplied diamines include 2 -Methyl- 1,3- diaminobutane and alkylhydropyπmidine. Further, it is believed that the diamines should be free of oxidation reactants to avoid diamme degradation and ammonia formation.

As is discussed in greater detail below, making the compositions free of hydrogen peroxide is important when the compositions contain an enzyme. Even small amounts of hydrogen peroxide can cause problems with enzyme containing formulations. However, the diamme can react with any peroxide present and act as an enzyme stabilizer and prevent the hydrogen peroxide from reacting with the enzyme. The only draw back of this stabilization of the enzymes by the diamine is that the nitrogen compounds produced are believed to cause the malodors which can be present in diamine containing compositions. Having the diamme act as an enzyme stabilizer also prevents the diamme from providing the benefits to the composition for which it was originally put in to perform, namely, grease cleaning, sudsmg, dissolution and low temperature stability. Therefore, it is preferred to minimize the amount of hydrogen peroxide present as an lmpuπty in the inventive compositions either by using components which are substantially free of as an enzyme stabilizer, because of the possible generation of hydrogen peroxide and/or by using non-diamine antioxidants even though the diamine can act malodorous compounds and the reduction in the amount of diamine available present to perform its primary role.

Preferred organic diammes are those in which pKl and pK2 are in the range of about 8.0 to about 11.5, preferably in the range of about 8.4 to about 1 1, even more preferably from about 8.6 to about 10.75. Preferred materials for performance and supply considerations are 1,3- bιs(methylamιne)-cyclohexane (pKa=10 to 10.5), 1,3 propane diamine (pKl=10.5; pK2=8.8), 1,6 hexane diamine (pKl=l 1; pK2=10), 1,3 pentane diamine (Dytek EP) (pKl=10.5; pK2=8.9), 2-methyl 1,5 pentane diamine (Dytek A) (pKl=l 1.2; pK2=10.0). Other preferred materials are the primary/primary diammes with alkylene spacers ranging from C4 to C8. In general, it is believed that primary diamines are preferred over secondary and tertiary diamines.

Definition of pKl and pK2 - As used herein, "pKal" and "pKa2" are quantities of a type collectively known to those skilled in the art as "pKa" pKa is used herein in the same manner as is commonly known to people skilled in the art of chemistry. Values referenced herein can be obtained from literature, such as from "Cntical Stability Constants: Volume 2, Amines" by Smith and Martel, Plenum Press, NY and London, 1975. Additional information on pKa's can be obtained from relevant company literature, such as information supplied by Dupont, a supplier of diamines.

As a working definition herein, the pKa of the diamines is specified in an all-aqueous solution at 25°C and for an ionic strength between 0.1 to 0.5 M. The pKa is an equihbπum constant which can change with temperature and ionic strength; thus, values reported in the literature are sometimes not in agreement depending on the measurement method and conditions. To eliminate ambiguity, the relevant conditions and/or references used for pKa's of this invention are as defined herein or in "Critical Stability Constants: Volume 2, Amines". One typical method of measurement is the potentiometπc titration of the acid with sodium hydroxide and determination of the pKa by suitable methods as described and referenced in "The Chemist's Ready Reference Handbook" by Shugar and Dean, McGraw Hill, NY, 1990.

It has been determined that substituents and structural modifications that lower pKl and pK2 to below about 8.0 are undesirable and cause losses in performance. This can include substitutions that lead to ethoxylated diamines, hydroxy ethyl substituted diammes, diamines with oxygen m the beta (and less so gamma) position to the nitrogen in the spacer group (e.g., Jeffamme EDR 148). In addition, mateπals based on ethylene diamme are unsuitable. The diammes useful herein can be defined by the following structure:

wherein R2.5 are independently selected from H, methyl, -CH3CH2, and ethylene oxides, C and C_v are independently selected from methylene groups or branched alkyl groups where x+y is from about 3 to about 6; and A is optionally present and is selected from electron donating or withdrawing moieties chosen to adjust the diamine pKa's to the desired range. If A is present, then x and y must both be 1 or greater.

Specific diam es suitable for use in the present invention are discussed in greater detail in U. S. Pat. No. 5,990,065, to Vinson et al., issued Nov. 23, 1999, which is hereby incorporated by reference.

Ratio of anionic to amphoteπc to diamine - In a preferred embodiment of the present invention, the LDL compositions contain anionic surfactant, amphoteπc surfactants, and diamme in a ratio of anionic: amphoteπc: diamine from about 100:40.1 to about 9:0.5: 1, by mole, preferably the ratio of the anionic: amphoteπc: diamme is from about 27:8:1 to about 11:3:1, by mole. It has been found that detergent compositions containing anionic surfactant, amphoteπc surfactant and diamme in this specific ratio range provide improved low temperature stability, deliver better grease removal and tough food cleaning benefits as well as improved hard water cleaning.

Calcium Or Magnesium Ions - The presence of calcium and/or magnesium (divalent) ions improves the cleaning of greasy soils for vanous compositions, i.e. compositions containing alkyl ethoxy carboxylates and/or polyhydroxy fatty acid amide. This is especially true when the compositions are used in softened water that contains few divalent ions. It is believed that calcium and/or magnesium ions increase the packing of the surfactants at the oil/water interface, thereby reducing mterfacial tension and improving grease cleaning. Compositions of the invention hereof containing magnesium and/or calcium ions exhibit good grease removal, manifest mildness to the skin, and provide good storage stability.

Preferably, the magnesium or calcium ions are added as a hydroxide, chloride, acetate, formate, oxide or nitrate salt to the compositions of the present invention.

The amount of calcium or magnesium ions present in compositions of the invention will be dependent upon the amount of total surfactant present therein, including the amount of alkyl ethoxy carboxylates and polyhydroxy fatty acid amide. When calcium ions are present in the compositions of this invention, the molar ratio of calcium ions to total anionic surfactant is from about 0.25 1 to about 2 1 for compositions of the invention

Formulating such divalent ion-containing compositions in alkaline pH matrices may be difficult due to the incompatibility of the divalent ions, particularly magnesium, with hydroxide ions When both divalent ions and alkaline pH are combined with the surfactant mixture of this invention, grease cleaning is achieved that is superior to that obtained by either alkaline pH or divalent ions alone. Yet, during storage, the stability of these compositions becomes poor due to the formation of hydroxide precipitates Therefore, chelating agents discussed herein below may also be necessary. The ions are present in the compositions hereof at an active level of from about 0.1% to

4%, preferably from about 0.3% to 3.5%, more preferably from about 0.5% to 1%, by weight Although either species of divalent ion provides benefits when included in a detergent composition, preferably the detergent compositions of the present invention contain no calcium ions. Solvents - The present liquid detergent compositions contain either diols or polymeric glycols or a mixture of both diols and polymeric glycols (polymeric glycols are composed of ethylene oxide (EO) and propylene oxide (PO) groups). In addition to diols and polymeπc glycols, a variety of other water-miscible liquids such as lower alkanols, diols, other polyols, ethers, amines, and the like may be used in the present invention. Particularly preferred are the C1-C4 alkanols. Suitable solvents are discussed in greater detail in the provisional patent application of Clarke et al., entitled "Diols and Polymeric Glycols for Improved Dishwashing Detergent Compositions", having P & G Case No. 7408 provisional serial no. 60/119,044, filed on February 8, 1999, which is hereby incorporated by reference.

When present the composition will preferably contain at least about 0 01%, more preferably at least about 0.5%, even more preferably still, at least about 1% by weight of the composition of solvent. The composition will also preferably contain no more than about 20%, more preferably no more than about 10%, even more preferably, no more than about 8% by weight of the composition of solvent. Composition pH Dishwashing compositions of the invention will be subjected to acidic stresses created by food soils when put to use, i.e., diluted and applied to soiled dishes. If a composition with a pH greater than 7 is to be more effective, it preferably should contain a buffering agent capable of providing a generally more alkaline pH in the composition and in dilute solutions. Dishwashing compositions of the present invention will thus contain from about 0.1% to 15%, preferably from about 1% to 10%, most preferably from about 2% to 8%, by weight, of a buffering agent. The pKa value of this buffering agent should be about 0.5 to 1 0 pH units below the desired pH value of the composition (determined as described above Preferably, the pKa of the buffering agent should be from about 7 to about 12. Under these conditions the buffering agent most effectively controls the pH while using the least amount thereof

Preferred inorganic buffers/alkalinity sources include the alkali metal carbonates, alkali metal hydroxides, sodium carbonate, and sodium hydroxide.

The buffering agent may be an active detergent in its own right, or it may be a low molecular weight, organic or inorganic material that is used in this composition solely for maintaining an alkaline pH. Preferred buffering agents for compositions of this invention are nitrogen-containing materials. Some examples are ammo acids such as lysine or lower alcohol amines like mono-, di-, and tπ-ethanolamine. The diamines, described in detail above, also act as buffering agents and are preferred buffering agents Preferred buffering system for use in the present detergent compositions include a combination of 0.5 % diamme and 2.5 % citrate and a combination of 0.5 % diamine, 0.75 % potassium carbonate and 1.75 % sodium carbonate. Other preferred nitrogen-containing buffering agents are Tπ(hydroxymethyl)amιno methane (HOCH2)3CNH3 (TRIS), 2-ammo-2-ethyl-l,3-propanedιol, 2-ammo-2-methyl-propanol, 2- amιno-2 -methyl- 1,3-propanol, disodium glutamate, N-methyl diethanolamide, 1,3-dιammo- propanol N,N'-tetra-methyl-l,3-dιamιno-2-propanol, N,N-bιs(2-hydroxyethyl)glycιne (bicine) and N-tπs (hydroxymethyl)methyl glycine (tπcme). Mixtures of any of the above are also acceptable For additional buffers see McCutcheon's EMULSLFIERS AND DETERGENTS, North American Edition, 1997, McCutcheon Division, MC Publishing Company Kirk and WO 95/07971 both of which are incorporated herein by reference.

Suds Booster - Another component which may be included in the composition of this invention is a suds stabilizing surfactant (suds booster) at a level of at least about 0.5%, preferably at least about 2%, more preferably at least about 5%. The composition will also contain no more than about 20%, preferably no more than about 15%, more preferably, no more than about 10% of said suds booster.

Suds stabilizing surfactants operable in the instant composition are: sultaines, complex betames, betaines, ethylene oxide condensates, fatty acid amides, amme oxide semi-polar noniomcs, and cationic surfactants. Also suitable as suds boosters are the polymeric suds stabilizers disclosed in the provisional application of Clarke et al., entitled "Diols and Polymeric Glycols for Improved Dishwashing Detergent Compositions", having P & G Case No 7408 provisional serial no 60/119,044, filed on February 8, 1999, which is hereby incorporated by reference.

Builder (Chelants) - The compositions according to the present invention may further comprise builders. As used herein, builders are chelants which remove and sequester the cations which cause water hardness, i.e. calcium and magnesium cations. The builders must be chosen with care, because certain builders and chelants such as citric acid and citrates impair the stability of amylase enzymes m LDL compositions. While not intending to be limited by theory it is believed that this instability is the result of competition for calcium atoms. Amylase enzymes are attracted to calcium atoms and are most stable when they bind can bind to calcium atoms. But because citric acid and citrates are also attracted and can bind to calcium atoms, they can reduce the number of calcium atoms available for enzymes to bond to and thus reduce the stability of the enzymes.

Accordingly, it is preferable that the present compositions should be free of chelants and builders which have relatively high calcium binding constants. Specifically, it is desirable that the present detergent compositions are free of chelants or builders for which the login of the calcium binding constant (Log K) is greater than 3.0, and preferably the present detergent compositions are free of chelants or builders for which the log,₀ of the calcium binding constant is greater than 1.5. For comparison, the following is a tabulation of known login calcium binding constant values for chelants which are widely used in detergent compositions.

Logm Ca²⁺

Binding Constant

(at 25°C. ionic strength = 0.1)

Citric Acid 3.5

Maleic Acid 1.1

Mahc Acid 2.0"

(* Measurement made at 20°C. These values are taken from: Critical Stability Constants, Vol 3 Other Organic Ligands (Edited by A. E. Martell & R. M. Smith) pp. 1 13, 125, and 161). Thus it is preferable that the present compositions should be free of chelants and builders which have a relatively high calcium binding constants when compared to the calcium binding constant of amylases. If the calcium binding constant of an amylase enzyme is represented by Ca_imrf it is desirable that the present detergent compositions are free of chelants having a calcium binding constant of equal to or greater than Ca₄,-_/, preferably the present detergent compositions are free of chelants having a calcium binding constant that is greater than 75% of the value of the amylase calcium binding constant (i.e. greater than 0.75*Ca_ftm_-). When there are multiple species of amylase enzymes present m the composition, the Ca_Aιm/ is assigned the value of the lowest calcium binding constant. In one embodiment of the present invention, the detergent compositions contain no builder material; if it is desired to use a builder, a builder selected according to the above limitations on the calcium binding constant is strongly preferred. Maleate is an example of one such material.

A general description of builder materials is contained in U. S. Pat. No. 5,990,065, to Vinson et al., issued Nov. 23, 1999, which is hereby incorporated by reference.

If detergency builder salts are included, they will be included in amounts of from 0.5 % to 50 % by weight of the composition preferably from 5% to 30% and most usually from 5% to 25% by weight.

Other Ingredients - The detergent compositions will further preferably comprise one or more detersive adjuncts selected from the following: soil release polymers, polymeric dispersants, polysaccharides, abrasives, bacteπcides and other antimicrobials, tarnish inhibitors, builders, enzymes, dyes, buffers, antifungal or mildew control agents, insect repellents, perfumes, hydrotropes, thickeners, processing aids, bπghteners, anti-corrosive aids, stabilizers antioxidants and chelants. A wide variety of other ingredients useful in detergent compositions can be included in the compositions herein, including other active ingredients, earners, hydrotropes, antioxidants, processing aids, dyes or pigments, solvents for liquid formulations, solid fillers for bar compositions, etc. If high sudsing is desired, suds boosters such as the Ci Q-C ^ alkanolamides can be incorporated into the compositions, typically at 1%-10% levels. The C \ Q- C14 monoethanol and diethanol amides illustrate a typical class of such suds boosters. Use of such suds boosters with high sudsing adjunct surfactants such as the amme oxides, betaines and sultaines noted above is also advantageous. COMPOSITION FORM AND METHOD OF USAGE Composition Form - The present liquid dishwashing detergent compositions may be in the form of either a microemulsion or a bicontmuous microemulsion By "microemulsion" or "conventional microemulsion" it is meant a thermodynamically stable mixture of oil and water m which a discontinuous domain is suspended in a continuous domain The discontmous domain is in the form of spherical droplets having radii of between 100 and 1000 A When the discontinuous domain is oil and the continuous domain is water, it is an oil-in-water microemulsion. When the discontinuous domain is water and the continuous domain is oil, it is a water-m-oil microemulsion See Surfactant Science Series, Volume 6 Emulsions and Emulsion Technology Part J (edited by Kenneth J Lissant), p. 127 Marcel Dekker, New York (1974), Surfactant Science Series, Volume 66 Industrial Applications of Emulsions (edited by Conxita Solans et al.), p. 2. Marcel Dekker, New York (1997)

By "bicontmuous microemulsion" it is meant a thermodynamically stable mixture of oil and water wherein two continuous, interconnecting and separate domains, separated by a surfactant interface, are present rather than there being both a continuous and a discontinuous domain. A bicontmuous microemulsion is classified as a Winsor Type III microemulsion P A Winsor, Chem Rev 68, p. 3-6 (1968); Surfactant Science Series, Volume 6 Emulsions and Emulsion Technology Part 1 (edited by Kenneth J. Lissant), p. 191-92 Marcel Dekker, New York (1997). Surfactant Science Series, Volume 66 Industrial Applications of Emulsions (edited by Conxita Solans et al.), p. 158, Marcel Dekker, New York (1997). When the detergent compositions are present in the form of a microemulsion or bicontmuous microemulsion, they will compπse (m addition to a selection of the ingredients described above)- (a) a microemulsion-forming solvent; (b) a liquid hydrocarbon component, and (c) an aqueous liquid carrier. Suitable examples of each of these components as well as overwell formulation directions are discussed m the provisional patent application of Mark L. Kacher et al., entitled "Light Duty Liquid Dishwashing Compositions in the Form of Microemulsions", filed on April 8, 1999, having serial no 60/128,351 and P&G Case No. 7504P, which is hereby incorporated by reference.

Method of Usage - The compositions of this invention can be used to form aqueous washing solutions for use hand dishwashing. Generally, an effective amount of such compositions is added to water to form such aqueous cleaning or soaking solutions. The aqueous solution so formed is then contacted with the dishware, tableware, and cooking utensils.

An effective amount of the detergent compositions herein added to water to form aqueous cleaning solutions can comprise amounts sufficient to form from about 500 to 20,000 ppm of composition in aqueous solution. More preferably, from about 800 to 5,000 ppm of the detergent compositions herein will be provided in aqueous cleaning liquor.

The following examples are illustrative of the present invention, but are not meant to limit or otherwise define its scope. All parts, percentages and ratios used herein are expressed as percent weight unless otherwise specified.

The following examples are illustrative of the present invention, but are not meant to limit or otherwise define its scope. All parts, percentages and ratios used herein are expressed as percent weight of the composition unless otherwise specified.

TABLE I

A light-duty liquid dishwashing detergent formula having the following composition is prepared:

Example 1 Example 2 Example 3 Example 4 Example 5

AES¹ 27.0 26.0 20.0 26.0 20

Amine oxide² 6.5 7.0 4.0 ~ 6.0

Noniomc³ 2.4 3.0 2 0 3.5 3.0

Diamme⁴ 0.6 1.0 0.5 - -

Suds boosting 0.8 1.0 0.5 ~ 0.7 polymer⁵

Polypropylene 1.4 1.5 1.0 ~ 10.0 glycol

Ethanol 6.0 5.8 2.0 5.6

Amylase 0.002 0.005 0.0005 0.002 0.001

NaOH to pH 8.5 to pH 9.5 to pH 9.0 to pH 9.0 to pH 8.5

Limonene - - - - 8.0

Water and Balance Balance Balance Balance Balance

Misc.

1: C₁₂-₁₃ alkyl ethoxy sulfonate containing an average of 0.6 ethoxy groups. 2: Ci -C]4 Amine oxide.

3: Noniomc may be either Cπ Alkyl ethoxylated surfactant containing 9 ethoxy groups or Cio Alkyl ethoxylated surfactant containing 8 ethoxy groups.

4: 1,3 bιs(methylamιne)-cyclohexane : Polymer is (N,N-dimethylamino)ethyl methacrylate homopolymer

Claims

WHAT IS CLAIMED IS:

1 A liquid dishwashing detergent composition characterized by:

(a) from 0.0001% to 5%, of an amylase enzyme; and

(b) at least 0.5% of a suds booster; wherein the composition has especially desirable greasy soil removal performance when used to clean heavily soiled kitchen articles and is substantially free of an ingredient selected from the group consisting of hydrogen peroxide and chelants having a Log K of greater than 3.0.

2. A composition according to Claim 1 wherein the composition is additionally substantially free of amine oxide.

3. A composition according to any of Claims 1-2 wherein the composition is further characterized by amine oxide, from which substantially all of the hydrogen peroxide has been removed so that the amme oxide contains less than 0.02% of hydrogen peroxide.

4. A composition according to any of Claims 1-3 wherein the amylase enzyme has a specific activity at least 25% higher than the specific activity of Termamyla at a temperature range of 25°C to 55°C and at a pH value m the range of 8 to 10, measured by the Phadebasa a- amylase activity assay.

5. A process for making a liquid dishwashing detergent composition containing substantially no hydrogen peroxide characterized by the steps of:

(a) providing two or more detergent ingredients, at least one of the detergent ingredients characterized by hydrogen peroxide;

(b) mixing together said two or more ingredients to form a detergent premix;

(c) adding an antioxidant to the detergent premix to form a peroxide-neutralized detergent premix; and

(d) adding amylase enzymes, and optionally one or more detergent adjuvants to the peroxide-neutralized detergent premix, wherein detergent adjuvants are substantially free of hydrogen peroxide.

6 A process according to any of Claims 1-5 wherein the detergent ingredients are characterized by amme oxide and wherein the amine oxide contains hydrogen peroxide, present as an impurity

7 A process for making a liquid dishwashing detergent composition containing substantially no hydrogen peroxide characteπzed by the steps of:

(a) providing a quantity of amme oxide containing hydrogen peroxide;

(b) adding a sufficient amount of an antioxidant to the quantity of amine oxide to from a detergent premix whereby the amount of hydrogen peroxide in the quantity of amine oxide is less than 0.02%; and

(c) adding amylase enzymes, and optionally one or more detergent adjuvants to the detergent premix, wherein the detergent adjuvants are substantially free of hydrogen peroxide.

8. A composition according to any of Claims 1 -7 wherein the composition is substantially free of chelants having a Log K of greater than 1.5.

9. A composition according to any of Claims 1-8 wherein the amylase enzyme has a calcium binding constant of Ca^_d and the composition is additionally substantially free of chelants having a calcium binding constant of greater than 0.75*Ca_ft,-_d .

10. A composition according to any of Claims 1-9 wherein the composition is characteπzed by 0.0001% to 0.05%.

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